Our company can product the excircle 20-320 sub-types of tungsten carbide knife
It is widely used in the processing of electronic circuit boards and printing, packaging, rubber, plastic and non-ferrous metal processing. 
We choose the ultra-fine nano-particles of tungsten cobalt materials, then couple with the heat after a pressure treatment, to remove sand hole, then high-temperature sintering.
We do that in order to extend the use of time and the safe. Our ring cutters using time is 2-3 times than ordinary tungsten steel,also 100 times more than 
high-carbon steel blades.
So the ring cutter become the most durable industrial machinery blade